Refrigerating machine



May 23, 1933. v E. KAGI 1,910,840

REFRIGERATING MACHINE Filed March 8, 1932 2 Sheets-Sheet 1 MLNJEIJTDFQ w E. KAGI REFRIGERATING MACHINE Filed March 8, 1932 2 Sheets-Sheet 2 INVENTDRy Q ,A'TTEI RN BK May 23, 1933 4 4 k A .1 s. 1.. w,

Patented May 23, 1933 UNITED: STATES PATENT OFFICE Eiun. 1am, on wrmm'rnun, swxr znnnann, ASSIGNOR '.120 THE rum or sunzmi FRERES SOGIETE.ANONYME, W 'I'.NCI.EIFtIIH'UR, SWITZERLAND nnrmenna'rme Macrame lp'pl ieation filed March 8, 1932, Serial No. 597,456, and in Switzerland August 17, 1931.

This invention relates to refrigerating machines and is particularly concerned with machines as described in U. S. application Ser. No. 451,933 filed May 13th 1930.- The I object of the invention is to provide an improved means for automatically returning from the evaporator to the compressor of a refrigerating machine oil used for lubrication and sealingv the clearances of the moving parts. For this purpose the chamber which is maintained at a lower pressure than the evaporator and to which the discharge pipe of the oil accumulator is connected, con- I stitutes' the suction chamber of an injector which is operated by the refrigerating medium supplied to the compressor.

According to the present invention the cross-sectional area of the admission nozzle of the injector is adjustable for the purpose of varying the suction in the oil discharge pipe in accordance with the working conditions in the machine. tapered needle is mounted adjacent the nozzle so that it is movable in the direction of the nozzle axis and it tapers in the. direction of the flow through the nozzle.

Preferably the position of the needle is automatically controlled by the admission pressure of the refrigerating medium supplied fromthe evaporator. The needle may be mounted on a movable member which is actuated'in accordance with the difference between this admission pressure and the atmosphericpressure or the pressure of the refrigerating medium in the condenser or the pressure on the outlet side of the admission nozzle. v Conveniently the needle is mounted on a movable piston-like member the two sides of which are respectively exposed to the two controlling pressures. The initial setting of the needle may be varied by adjusting by hand the tension of a spring acting on the movable member carrying the needle.

If desired, instead of automatically con' trolling the position of the needle in accordance with the admission pressure, it may be controlled by a thermostat or other tempera. ture responsive device associated with the evaporator so that the cross-sectional area Conveniently a mg drawings.

Fig. 1 shows a refrigerating plant according to the invention diagrammatically Figures 2 to 5 show different constructions of the injector in sectional side elevations.

In igure 1 the refrigerating medium is supplled to the compressor by the pipes H from the evaporator E.

is discharged through the pipe (1!. This discharge pipe (1 opens into the suction chamber of an injector a, b which is so connected to the suction pipe 6 of the compressor C that it is operated by the refrigerating medium. Oil collecting in the collector A is thus drawn up into the suction chamber of the injector a, 6 without appreciable loss of pressure of the refrigeratin medium and is'carried away by the rapidly moving refrigerating medium and returned to the compressor in an atomized state.

In the injector shown in Figure 2 the refrigerating medium from the evaporator passes from'pipe a through the admission The evaporator has an ail collector A, from which oil A tapered needle 9 is, mounted on a piston-like member Zr, which moves in a cylinder formed in the casing f of the injector, so that the needle is tapered in the direction of the flow of the refrigerating medium from the pipe 0 through the admission nozzle a. Thus b y adjusting the posiof the nozzle a and acts to vary the effective cross-sectional area of this nozzle.

The upper side of the piston is is connected to the top of the injector casing by a flexible corrugated diaphragm h which does not prevent the free movement of the 100 tion of the piston is the needle 9 is moved along the axis spring a is arranged between the upper side of the piston 70 and a plug Z which is mounted in the top of the casing so that it can be rotated by hand to vary the tension of the spring 71 by means of a key which fits within a square or rectangular recess in the top thereof.

When the refrigerating machine is started the pressure in the evaporator will usually be high and the refrigerating medium drawn into the injector will thus be comparatively heavy so that the effective weight of the medium passing through the admission nozzle past the end of the oil pipe will be comparatively large. Under these conditions the kinetic energy of the refrigerating lmedium inthe admission nozzle will be su cient for inducing in the pipe (3 a suction pressure which is lower than that in the pipe 0 and, is quite sufiicient' for pumping the oil from the collector into the injector and thence back to the compressor. When the machine has been working for an appreciable time the evaporator pressure will decrease with the result that the refrigerating medium or vapour drawn in will become lighter. The kinetic energy of this vapourin the admission nozzle is thus reduced and may even decrease to such a value that it is ins'uflicient for pumping any oil.

This decrease in the effective weight of refrigerating medium passing through the admission nozzle is, in acordance with the present invention, compensated for by decreasing the area of the nozzle so as to maintain the kinetic energy at the desired value.

When the admission pressure decreases the piston is moves downwards thus reducing the cross-sectional area of the admission nozzle and consequently increasing the kinetic energy of the vapour passing through the nozzle. The tension of the spring 2' is set by adjusting the screw plug Z so that the piston 70 moves to adjust the position of the needle 9, in accordance with changes in the pressure of the refrigerating medium pumped from the evaporator, to maintain the kinetic energy of the vapour passing through the admission nozzle a at substantially the correct value for pumping the requisite quantity of oil irrespective of changes in the operating conditions of the machine.

In themodified construction shown in Figure 3 the upper side of the piston I0 is formed as a cylinder for another iston p the upper side of which is connected y a corrugated flexible diaphragm a, similar to the diaphragm h, to a screw plug 9 in the top of the in'ector having an aperture connected bya pipe 0 to the condenser of the machine. The upper side of the piston 12 is thus exposed to the condenser pressure the sleeve 11.

furnishing a gas tight joint between the plug g and this cylinder. A spring on is arranged between the up er side of the piston lo and the under side 0? the piston 12 so that movements of the piston 2 due to variations in the pressure in the condenser are communicated to the piston is through this spring, the initial tension of the spring m being adjusted by varying the position of the screw plug g.

It will be apparent that this modified arrangement acts in a manner similar to that shown in Figure 2 with the exception that the movements of the piston are controlled in accordance with variations in the difference between the pressures of the refrigerating medium from the evaporator admitted through the pipe 0 and the pressure in the condenser.

In the construction shown in Figurefi the upper surface of the piston is is connected through a duct at the top of the injector casing and a pipe 1" to the oil supply pipe (1 near the point at which it is connected to the injector casing. The piston is is thus controlled in accordance with variations in the diiference between the pressure of the refrigeratin medium drawn from the evaporator and t e pressure onthe outlet side of the admission nozzle. It is to be noted that as the pressure on the outlet side of the nozzle increases due to the decrease of the kinetic energy in the nozzle the piston 70 moves downwards thus decreasing the area of the nozzle so that the kinetic energy in the nozzle is again raised to the required value.

This construction also differs from the arrangement shown in Figure 2 in that the vprovi ed for the top of the recess in the easing into which the plunger Z fits so as to ensure an air tight joint in the part of the casing above the piston k. I

In the construction shown in Figure 5 the needle 9 constitutes the lower end of a rod m which is mounted in a bearing carried by the casing f so that it is coaxial with the admission nozzle a. The upper end of the rod .1; is connected by links to the rod of a piston to mounted on a flexible diaphragm v one end of which is connected to the casing f and the other end to the piston w. The interior of the diaphragm *v communicates, by means of a pipe u, with a temperature responsive device such as a thermostat (not shown) which is arranged on or in, the

, neighbourhood of the evaporator. .The diaphragm 0 thus expands or contracts in accordance with changes in the temperature of the evaporator, the movement of the diaphragm causing corresponding movement of the piston w and thus, through the'link mechanism and rod w, of the needle 9.

It will be appreciated that the above description is by Way of example only and that detailed modifications may be made in the construction and arrangement of the incross-sectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine.

' 2. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor fol-returning the lubricant and the refrigerant from said evaporator directly to said compressor and including an injector'having a pressure chamber and a suction chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the sues tion chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the crosssectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction .in the oil discharge pipe in accordance with the working conditions in the maclnne, said nozzle having a needle-member therein, to control the cross-sectionalv area thereof, said 'member being tapered in the direction of flow through the nozzle.

3. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refri erant from said evaporator directly to said compressor and including an injector having a pressure chamber and a suction chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the sa1d collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the crosssectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle-member therein to control the cross-sectional area thereof, said memher being tapered in the direction of flow through the nozzle, and being movable in the direction'of the nozzle axis.

4. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refri erant from said evaporator directly to said compressor and including an'injector having a pressure chamber and a suction chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the suction chamber of said injector, a

pipe leading from the pressure chamber of said injector directly to the compressor, the cross-sectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle-member therein, to control the cross-sectional area thereof, said member being tapered in the direction of flow through the nozzle, and means for automatically varying the position of said needle in accordance withvariations in the pres sure of the refrigerant admitted thereto.

5. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refrigerant from said eva orator directly to said compressor and inc uding an injector having a pressure chamber and a suction chamber, a lubricant collectorfor collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the cross-sectional area of the ad mission nozzle of the injector being adjustable for the purpose of controlling the suc tion in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle-member therein, to control the cross-sectional area thereof, said memberbeing tapered in the direction of flow through the nozzle, and means for automatically varying the position of said needle in accordance with the difference between the pressure of the refrigerant admitted thereto and that of the atmosphere.

6. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refrigergravity lubricant from the refrigerant, a'

discharge pipe connecting the said collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor,

the cross-sectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle member therein, to control the cross-sectional area thereof, said member being tapered in the direction of flow through the nozzle, and means for automatically varying the position of said needle in accordance with the difference between the pressure of therefrigerant admitted thereto from the evaporator and that of the refrigerant in the condenser.

7. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refrigerant from said evaporator directly to said compressor and including an injector having a pressure chamber and a suction chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the cross-sectional area of the admission nozzle of the injector being adjustable for the. purpose of controlling the suction in the oil discharge pipe in accordance with the -work ing conditions in the machine, said nozzle having a needle-member therein, to control the cross-sectional area thereof, said member being tapered in the direction of flow through the nozzle, and means for automatically controlling the needle in accordance with the difference in pressure between the pressure of the refrigerant admitted thereto and the pressure on the outlet-side of the nozzle.

8. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant'and the refrigerant from said evaporator directly to said compressor and including an injector having a ressure chamber and a suction chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the suction chamber of said injector, a pipe lead ing from the pressure chamber of said injector directly to the Compressor, the crosssectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a ,needle therein, said needle being mounted "a pressure chamber and a suction chamber, a

lubricant collector for collecting by gravity lubricant from the refrigerant, a discharge pipe connecting the said collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the

' cross-sectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle-member therein, to control the cross-sectional area thereof, said member being tapered in the direction of flow through'the nozzle, a movable member for carrying the needle, a spring acting thereon, and means for manually adjusting the effective-force of said spring to effectuate the initial setting of said spring.

10. A refrigerating machine, comprising a main evaporator, a compressor, and a means between the evaporator and the compressor for returning the lubricant and the refrigerant from said evaporator directly to said compressor and including an injector having a pressure chamber and a suction 'chamber, a lubricant collector for collecting by gravity lubricant from the refrigerant,

a discharge pipe connecting the said collector to the suction chamber of said injector, a pipe leading from the pressure chamber of said injector directly to the compressor, the cross-sectional area of the admission nozzle of the injector being adjustable for the purpose of controlling the suction in the oil discharge pipe in accordance with the working conditions in the machine, said nozzle having a needle-member therein, to control the cross-sectional area thereof, said member being tapered in the direction of flow through the nozzle, and a temperature-responsive device operatively connected to the evaporator, said device being connected to said needle so as to control the position of same in accordance with the temperature ofthe evaporator.

EMIL KAGI. 

